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Stayed cable force tentative test method

A cable force and cable technology, which is applied in the field of nondestructive testing of bridge structures, can solve the problems of retention, lack of conversion relationship between frequency and cable force, and inability to calibrate cable force and frequency conversion coefficient.

Inactive Publication Date: 2021-01-22
CCCC SECOND HIGHWAY ENG CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The present invention provides a tentative test method for the cable force of the cable stay, which aims to overcome the need to calibrate the conversion coefficient of the cable force and frequency through sensors in the traditional cable force test method in the prior art. The problem of calibrating the conversion coefficient of force and frequency; the second purpose is to overcome the fact that most of the bridges in the prior art fail to retain the relevant data of the cable force and frequency after completion, especially before and after the installation of the shock absorber damper. The test data of the cable force and frequency of the cable-stayed bridge leads to the lack of accurate conversion relationship between the frequency and the cable force when the cable force of the cable-stayed bridge is dynamically measured during the operation period, so it is impossible to accurately carry out the cable force of the cable-stayed bridge during the operation period. test question

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  • Stayed cable force tentative test method
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  • Stayed cable force tentative test method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] A cable force trial test method for a stay cable, comprising the steps of:

[0034] 1) Obtain the frequency values ​​of all the cables of the cable-stayed bridge;

[0035] 2) Analyze the moving load influence line of the cable-stayed bridge to form the influence matrix of load-cable force increment;

[0036] 3) Using the influence matrix of load-cable force increment, formulate a loading scheme for each cable to be tested, and obtain the cable force increment;

[0037] 4) According to the loading scheme formulated in step 3), each cable is loaded sequentially, and the frequency values ​​of the cables under loading are tested respectively to form a frequency vector under loading;

[0038] 5) Use the frequency value of the cable and the frequency vector under loading to calculate the conversion factor between the cable force and the frequency;

[0039] 6) Use the conversion coefficient of cable force and frequency and the frequency value of the cable to obtain the cable...

Embodiment 2

[0042] On the basis of Embodiment 1, further, when the frequency values ​​of all cables of the cable-stayed bridge are acquired in the step 1), it needs to be carried out under the condition of closed traffic at night. Improve the accuracy of the obtained frequency value of the cable to ensure safe and accurate measurement work.

[0043] Further, the method for obtaining the frequency value of the cable in step 1) is: arranging a vibration pickup or an acceleration or velocity sensor on the cable, testing the dynamic response time history of the cable, and then obtaining the frequency value of the cable through spectrum analysis. Natural frequency, that is, the frequency value of the cable. This method is simple and easy to operate, and it is convenient to obtain accurate cable frequency values.

[0044] Further, the step 2) uses the finite element method to analyze the moving load influence line of the cable-stayed bridge. Analysis by finite element method is a well-known a...

Embodiment 3

[0057] For a cable-stayed bridge, the span layout is (89.5+220.5+89.5)m, the model of the longest cable-stayed cable is 27Ф15.7mm, the linear density is m=410.3N / m, the length l=103m, and the dead load Cable force T=2.6×10 6 N, the frequency of the cable is estimated by using the string theory formula of the cable:

[0058]

[0059] The test accuracy of the existing frequency tester can reach 0.005 Hz. Through repeated measurements or the development of a frequency tester with higher precision, it can effectively ensure that the accuracy of the cable force identified by the method of the present invention meets the engineering needs.

[0060] Estimation adopts the cable force identification accuracy of the present invention as attached figure 2 (the cable force increment is 0.2 times the dead load cable force), attached image 3 (The frequency identification accuracy is 0.02Hz). attached by figure 2 , attached image 3 It can be seen that the higher the frequency ide...

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Abstract

The invention belongs to the technical field of bridge structure nondestructive testing, and particularly provides a stay cable force tentative test method, which comprises the following steps of carrying out a full-bridge stay cable frequency test under the condition of traffic closure at night; analyzing a cable-stayed bridge moving load influence line by utilizing a finite element to form an influence matrix of a load-cable force increment; formulating a loading scheme to enable a to-be-tested stay cable to generate a preset cable force increment and a preset frequency increment; calculating a conversion coefficient of the cable force and the frequency of the stay cable by utilizing the calculated cable force increment and the actually measured frequency; and calculating the constant-load cable force value of each stay cable by utilizing the actually measured frequency of each stay cable and the calculated conversion coefficient, so that the problem that the conversion coefficient of the cable force and the frequency of the stay cable cannot be calibrated in an operation period is solved. According to the invention, the conversion coefficient of the cable force and the frequencyof the stay cable is identified by skillfully utilizing a load probing method, so that the cable force test of the stay cable can be carried out under the condition that a conventional dynamic testerdoes not calibrate the frequency cable force conversion coefficient.

Description

technical field [0001] The invention belongs to the technical field of non-destructive testing of bridge structures, and in particular relates to a cable-stayed cable force test method. Background technique [0002] There are usually the following methods for cable force testing of cable-stayed bridges: oil pressure gauge method, pressure sensor method, vibration frequency method and magnetic flux method. Among them, the frequency method is widely used in the construction process of cable-stayed bridges and the detection of cable forces after completion of the bridge because of its simplicity and ease of operation. The specific principle is to collect the dynamic response time history by arranging a vibration picker at a certain distance away from the end of the cable, and then obtain the first few natural vibration frequencies of the cable through spectrum analysis, and then use the natural frequency of the cable and the cable force The conversion relationship of the cable...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01L5/04
CPCG01L5/04
Inventor 肖军霰建平李松
Owner CCCC SECOND HIGHWAY ENG CO LTD